1. Field of the Invention
The present invention relates to a non-contact scanning system and more particularly to a three dimensional non-contact scanning system for use in various applications including reverse engineering, metrology, dimensional verification and inspection, which includes a scanner assembly carried by an arcuately configured gantry assembly and a fixture assembly for carrying the work piece and enabling an spherically shaped scanning envelope to facilitate the formation of a three dimensional model of an object or work piece.
2. Description of the Prior Art
Various scanning systems are known in the art for scanning objects for either dimensional verification or reverse engineering of a work piece. Examples of such systems are disclosed in U.S. Pat. Nos. 5,784,282; 5,848,115; 5,999,642; 6,028,955; 6,031,225; 6,101,268; 6,226,395; 6,285,959; 6,542,249; 6,570,715; 6,571,008; 6,628,819; 6,687,328; 6,703,634, 6,708,071; 6,738,507; 6,834,253; 6,850,331; 6,912,293 and 6,917,701, hereby incorporated by reference. Such systems normally include a movable fixture for carrying the work piece and a stationary or movably mounted scanner for scanning the work piece. Many known scanners are used for three dimensional scanning of an object. For example, U.S. Pat. No. 5,848,115 discloses a three dimensional scanning system which utilizes computerized tomography, used for dimensional verification of a work piece. The scanning system includes an x-ray source and detector (hereinafter referred to as an “x-ray scanner”) mounted to a gantry which allows the scanner to move linearly along the X and Z axes. The work piece to be scanned is mounted on a fixture that includes rotatable table which is also mounted for rectilinear movement along the X and Y axes. U.S. Pat. Nos. 5,999,642; 6,101,268; and 6,226,395 also illustrate a three dimensional scanning system which includes a scanning device (in this case a camera) mounted on a gantry which allows the scanning device to move linearly along the X, Y and Z axes relative to the object to be scanned. U.S. Pat. No. 6,628,819 discloses a three dimensional scanning system which includes a fixture for carrying a work piece to be scanned, formed as a rotatable table. The scanner is fixed relative to the rotatable table so that locator markings on the rotatable data are always in the field of view of the scanner. U.S. Pat. No. 6,687,328 also discloses a three dimensional scanning system which includes an x-ray scanner mounted for movement relative to the X-Y axes. The scanning system also includes a fixture for carrying the work piece to be scanned. The fixture is mounted under the platform and is configured to be rotated about the X and Y axes.
The configurations of the three dimensional scanning systems mentioned above constrain the size the work piece that can be scanned. In order to solve this problem, U.S. Pat. No. 6,738,507 discloses a three dimensional free standing scanning system for imaging relatively large objects on the ground or in situ. This scanning system includes a scanners mounted at the end of a free standing robot arm configured with multiple degrees of freedom that allows the scanner to scan the object from many different positions and angles.
The configurations of the various three dimensional scanning systems mentioned above also result in other problems. For example, such configurations require multiple scans in order to form a three dimensional model of the work piece. As such, these systems require computationally intensive calculations to spatially orientate each of the two dimensional images from the scanner in order to form a three dimensional model of the work piece. Thus there is a need to provide a three dimensional scanning system which facilitates formation of a three dimensional model of the work piece.